The invention provides a steel-rail wear measurement device based on machine vision, which comprises a main control panel, a power panel, a laser control panel, and a video panel. The power panel is used for providing a stable direct-current voltage for the main control panel, the laser control panel and the video panel. The laser control panel is electrically connected with two high-power lasers. The video panel is electrically connected with two CCD cameras. The main control panel is connected with the power panel, the laser control panel, and the video panel, and used for controlling the on-off and intensities of the two high-power lasers and controlling the shooting actions of the two CCD cameras. The invention also provides a grinding strategy method for steel-rail wear according to the measurement device. According to a planned grinding quantity, a proper grinding speed of a steel-rail grinding car, the grinding power, and the motor distribution of different angles are calculated, and the steel rail is grinded. The steel-rail wear measurement device based on machine vision has the beneficial effects that the planned grinding area of the steel rail on side can be calculated according to different zones, and shortcomings of large amount of labor, poor environment, low efficiency and the like of the measurement mode of manual and mechanical contact can be overcome.